Intermittent stock-feeding machine



Jan. 30, 1951 J. B. M FALL INTERMITTENT STOCK-FEEDING MACHINE 5 Sheets-Sheet 1 Filed June 9, 1947 Ihmcntor JOE 5. Mc FALL Jan. 30, 1951 J. B. MCFALL 2,540,004

INTERMITTENT STOCK-FEEDING MACHINE Filed June 9, 1947 5 Sheets-Sheet 2 IIIHWHHIHIHI" Gttornegs Jan. 30, 1951 J. B. MQFALL 2,540,004

' INTEPMITTENT STOCK-FEEDING MACHINE Filed June 9, 1947 5 Sheets-Sheet 4 Snncntor J05 B. MC Em W J-W Jan. 30, 1951 J. B. MCFALL 2,540,004.

INTERMITTENT STOCK-FEEDING MACHINE Filed June 9, 1947 5 Sheets-Sheet Bnneutor J05 B. Mc FALL Patented Jan. 30, 1951 UNITED STATES PATJEN T O F F ICJE Joe B. li/icFall, Seattle, Wash.,.assignor to United .StatesBlywood Corporation, .Seattle, Wash, a

corporation of New York Application June 9, 1947,:Serial No.75'3;523

10 Claims. 2

invention relates to automatic stockcutting machines and similar devices employing retractable operating tools and coordinated means for advancing the material from which the stock is cut, incrementally, or in step-by-step manner, past an operating zone or station. The .stock out by such a machine may, for example, be substantiallysquare pieces of veneer to :be used for patches to :fi ll holes in wood *veneer :made in removing knots, pitch pockets and other defects. In its illustrated forms the invention has :been described by reference to :its application in such patch stock cutting machines.

The automatic'meansrin such machines foradvancing the stock through the operating izonein coordination with the stroking :of the operating tool must operate very accurately to maintain uniformity in the size of the stock out In the plywood industry, patching damaged or .faulty areas in veneer, 'it .is necessary that the pieces of stock for the plugs or patches be precisely-uniform in dimension to :be handled properly by the patching machine. The number of patch stock pieces required bya manufacturer often-approaches a value which cannot economically be produced 'by manually controlled :tools.

With this in view, an object of the invention is to provide .an improved patch stock cutting machine adapted for cutting automatically one or more pieces of stock material accuratelyinto uniform lengths. A more specific object is .to provide an inexpensivareliable and accurate .automatic work advancing mechanism adapted to be operated in coordinationwith thestrohingsmotion of a retractable power-saw or other :too1,'without marring the stock or producing excessive shock or vibration in the apparatus. Economy 'of motion in the operation of the machine parts long life, minimum adjustment and adaptability for handling stock of id-ifierent dimensions are understood objects.

These and otherobjects and advantages of the invention, .including .its various novel features and details of construction and operation, are described hereafter.

Figure 1 15a sideaelevati'on'view of apatchistock cuttingmachinefembodying the invention, viewed from the side away Jfromthe resting position f thes'aw Figure 2 is an end elevation view and Figure 3 is a plan view of the'same machine.

Figure :4 isvan enlarged side elevation *Vi'BWiQ'f a portion of the machine, principally illustrating one .form 'df gstock advancing mechanism.

=Figure5 (sheet 1) :is-a detailed end view, showing a mechanism to support a stack of severed sections of stock just beyond the saw, after cutting.

Figures 6, 7, and 8sare schematic electromechanical diagrams in top perspective, respectively illustrating three sequential ,phases of an operating cycle of this machine.

Figure 9 is a partial elevation side view of the patch stock cutting machine embodying an .alternative type of stock advancing means, and Figure 10 is an end elevation view of this machine seen looking -at :the :saw end thereof, while Figure 11 is atop perspective diagrammatic view illustrating :the means :for controlling the stock advancing mechanism in coordination with the movable saw carriage.

Customarily, patch stock cutting-machines are designed .for handling wood :strips advanced .horizontally between guides into the cutting :zone. The cut-ofi saw is usually supported on .a swinging carriage arm for-stroking it through the :zone intermittently, :each time the :stock has been postioned for-cutting. Manualcuttingapparatus cannot be operated rapidly because of the attention required both in :the .control of the saw carriage :arm and in feeding and removing the stock.

In the machine-of Figures V1 to 5, inclusive, @the saw carriage arm is automatically stroked through the cutting .zoneintermittently, :in timed relation with the forward 'step-by-step-.advancement of the stock. The stock materials .are thus out into uniform lengths automatically without attention of an operator other than to supply strips and remove cut-stock.

The machinecomprises a framestructure 10 on which is mounted a strip-supporting table [2 (Figures 4 and 5-) slotted to-receive a saw I 8. The shaft carrying the saw is journaled horizontally in a suitable mounting 20 car-ried'at the upper end of a swinging carriage 14 and .is driven .by-a belt 22 .connecting ipulleys 24. The lower pulley is rotated by an electric motor :26 mounted on the under side of the carriage-arm. Figure 2, such arm is pivotally mounted at its base .011 :a horizontal shaft 16 journaled inzthe base of the machine. The armis :shown in solid lines inrits return or resting position and .in dot-dash )lines in its forward position atithe end of the cutting stroke.

For oscillating the saw back and iorth intermittently through the cutting zone a quick-return motion type power drive .has 'beenprovided for swinging the arm I4, in the tformcof a specially designed rotarycamifl engagmg a cam i01- and its other end anchored to a crosspiece 38 of the machine frame l0. In accordance with the cam design, when the motor 32 is in operation the,

stroking movement of the carriage arm is such that the saw is advanced at a rapid rate into cutting position, moved relatively slowly through the cutting zone, first forwardly and then rearwardly, and quickly returned to its resting position, dwelling for a period at either end of its stroke. During withdrawal of the saw from the cutting zone to its rest position, a new section of the strip stack is advanced through the cutting zone transversely of the path of the saw.

When setting up the machine for operation a stack of stock material at, such as veneer strips, to be cut is placed on the supporting table i2 under the pressure of a holddown rider member 42, The stock, in being fed towards the cutting zone, is engaged intermittently by a retractable platform 44, representing any suitable stockengaging device actuated in a manner to be described, and comprising part of the stock feeding mechanism. When so engaged, the stock is raised free of the support l2, carried toward the cutting zone by the feed stroke of the platform and returned to the table I2 in a new cutting position. The platform then retracts from engagement with the stock and is returned transversely of the stock to its starting position for the succeeding feed stroke. To allow passage of the platform to engage the stockfor a feeding operation, the supporting table [2 is slotted at 4'6, although the platform might be arranged otherwise alongside the support, such as being split and straddling the support.

The motion of the platform is effected by fluid actuating means acting through a reciprocative rod 48 and comprising a fluid cylinder 50 housing a coacting piston fixed to a piston rod 52 which, in turn, is pivotally connected to the rod 38. Movement of the piston and rod 52 is determined bycontrolling the supply of fluid under pressure to the opposite ends of the cylinder, the resulting reciprocation of rod 48 being converted into motion of the platform by the feed mechanism to be described, first laterally outward or away from such rod and then lengthwise in one direction,

and subsequently laterally inward or toward such rod and lengthwise in the return direction.

The feed mechanism includes a toggle linkage, in one form, shown in Figures 1 to 8, inclusive, comprising dual pairs of links 54 and 56, connected by common pivots to the rod 4-8, the upper links being pivotally connected to lugs projecting downwardly from the underside of the platform 44, and the lower links connected to lugs projecting upwardly from a horizontal friction or resistance slider member 58, near its opposite ends. Strips 68 are pressed against the slider member by loading compression springs i8, encircling bolts mounted on a slider supporting member 12 and extending through holes in strips 68. The pressure of such springs may be varied by adjustment of springs retaining nuts it threaded on these bolts, to vary their degree of compression for altering the amount of friction applied to the slider.

The linkage composed of links 5' and s contracted prior to initiation of the outward or feed. movement of piston rod 52 and rod 48. The slider initially is held against lengthwise movement by the friction strips 68 pressed against it. A vertical post 86, mounted on the underside of platform 44 and projecting downward through a hole in slider 58, interconnects such platform and slider to maintain them always in lateral registry, so that the platform is prevented from moving lengthwise as long as the slider is held against such movement. Such post, however, does not prevent relative separating movement of the slider and platfrom in a lateral direction.

As the rod 48 is moved outward, its first action is to expand the linkage by moving its links 54 and 55 toward alignment while the slider 58 is held stationary, and as the linkage is thus expanded it exerts a considerable upward thrust against the platform 44, thereby raising the stock off its support l2. Such expansion of the linkage is limited by the end of rod 4'8 abutting the post 65, which is secured to the platform in the path of the rod, such permissible linkage eX- pansion being sufiicient for the platform to lift the stock free of the supporting table l2, so that it may be advanced. When the platform has thus been raised, the direct pressure of rod 48 against the stop post overcomes the friction of the clamping bars 68 on the slider 58, so that the entire assembly, including the slider, the platform in raised position, and the linkage in expanded condition moves forward, thus advancing the stock through the cutting zone. During such movement, the post 66 positively interconnects the platform and slider for conjoint lengthwise movement.

In Figure 4, the parts drawn in solid lines have been shown just as the linkage reaches its limiting expanded position effected by the endwise outward thrust of the piston rod 52 and rod 48. In Figure 4, the parts are shown in dot-dash lines prior to initial reciprocation of piston rod 52 and rod 48. The dot-dash line showing illustrates the parts in their positions of maximum advance, having fed across the cutting zone the next section of the strip stack to be out off. The return of the parts to their original positions oc-' ours in reverse sequence, platform 44 being retracted toward rod 48 upon initiatio of the reverse movement of such rod, because of the friction exerted on slider 58 by the springs 18.

The amount of linkage contraction is limited by a stop-rest 64 mounted on the slider, onto which the rod 48 drops as it approaches the slider member. By such contraction of the linkage, the platform 44 is depressed below the upper surface of the table l2 so that again the stack of strips rests on the table. Continued retracting movement of piston rod 52 and rod 48 will withdraw the rod, linkage, slider and the platform assembly into the left dot-dash line position of Figure 4 ready for initiation of the next feeding movement. To accommodate the rising and falling movements of rod 48 during expansion and contraction of the linkage, it is pivotally connected to piston rod 52, and the cylinder 5!] is pivotally mounted at its end remote from piston rod 52, on a pin 56 retained in a bracket 62 which is bolted to the frame 14' of the machine as shown in Figures 1 and 3.

The holddown rider member 42 which presses the stock firmly against the table l2 during cutting and against the platform 44 during feeding of the stock, is provided with a lower framework 16fhaving stock-engaging rollers I8 located at spaced intervals along the stocks line of advance. The amount of downward pressure thus exerted is determined by a weight 80 upheld by a vertical post 82 fixed to the frame I6. The advantage of using a weight rather than a spring type of device lies in the resulting constant pressure maintained against the stack of veneer strips irrespective of its height. The rider is free to move vertically when the stock is raised by the feeding platform 44, because it derives its lateral support from a vertical supporting member 84 provided with laterally projecting lugs 36 having holes through which slides the vertical post 82. The rider may be lifted for inserting fresh stock beneath it by swinging a lever member 33 pivoted on a pin 90 carried by an upright mounting 92.

To guide the stock as it is advanced toward the saw, guidemeans, such as a vertical roller TI and vertical plates I9 and 8 I, may engage opposite sides of the work. To support the end of long strips of stock remote from the cutting zone a horizontal supporting roller 83 can be mounted in a position spaced from table I2, which reduces the drag of the stock when it is lifted by the platform and carried forward. The saw is shown protectively shielded by meansof suitable hoods 9|. In addition, new sections of stock out on? by the saw are lifted slightly and rolled forward by the device illustrated in Figure 5, comprising an arm 85 pivoted intermediate to its ends and carrying at one end a free turning roller 87 which is normally projected up through a suitable slot in the table III into contact with the work by counter weighting the other end of the arm.

In controlling the introduction of fluid into the fluid cylinder 56 for operating the work feed mech-. anism, a fluid system is provided having a pair of two-way control valves 93 and 95 (see Figures 3, 6, '7 and 8). In operation, the valves are alternately opened to the through-position, for transmitting fluid, such as compressed air, to the cylin der through the pipes 95 and 96 from a common supply pipe 98 and regulator Hill, and closed to the exhaust position for relieving the fluid pressure in the cylinder into pipes 91 and 99. Conveniently, the valves may be solenoid controlled as shown, separate solenoids I02 and I04 being connected to each of the valves.

The solenoids are connected to carriage-armoperated control switches I II] and I I I, the switches being shown in different operative positions in Figures 6 to 8, inclusive, in their relation with the other functional components of the control system of the machine. In these figures the mechanical parts of the system have been shown rather diagrammatically for purposes f clarity, although they bear the same numerical designation as before. Normally open switch IIB, closable to control valves 93 and 95 for effecting retraction of rod 48, is adapted to be closed by a suitable actuating member, shown as a switchengaging finger I I2 projecting forwardly from the saw carriage arm I4, which contacts the switch on the forward stroke of the saw. Normally open switch II4, closable to control valves 93 and S5 for effecting projection of rod 48 to feed the stock forward, is adapted to be closed on the return stroke of the saw by engagement with it of an actuating member shown as the finger H6 projecting rearwardly from the back of the carriage arm. Switches H2 and II are in circuit with solenoids I52 and IM connected to move valves 93 and. 95, respectively. Closing power switch I I? III) applies voltage over input leads II8 to the circuits, includin the carriage arm drive motor 32.

In Figure 6, illustrating the extreme forward position of the saw following a cut, solenoid I02 is energized through closed switch I I0, opening valve 5-33 to connect the supply of fluid under pressure to the left end of cylinder 50, and solenoid I04 is deenergized, switch I I4 being open, so that valve is arranged to exhaust the right end of cylinder 53. The pressure of the fluid in the left end of such cylinder retracts the rod 33 and the platform 45. This condition is first reached, during the forward movement of the carriage arm M, at the instant switch III! is closed by the finger I I2.

In Figure '7 the machine has just left the operational phase of Figure 6 and has reached the stage where the saw is substantially fully re tracted and the stock advancing stroke of rod 48 is about to commence. By the rearward movement of arm I4 finger II2 has been withdrawn from engagement with switch IIB, enabling it to open, and switch I It has been closed by engagement of finger IIS with it, resulting in energization of solenoid I M to open valve 95 for connecting the supply of fluid under pressure to the right end of cylinder 59. Since solenoid I02 is deenergized, valve 93 is closed to exhaust the left end of cylinder 56, thereby providing a stock feeding thrust to the rod as. Because of the substantial dwell time of the saw carriage arm I l in this rearward position, occasioned by the nearly constant radius of the larger end or lobe of cam 28, a considerable fraction of the operation cycle is thus aflorded for the mechanism to advance the stock. 7

Following the dwell period of the sawarm in its rearward position, its swing forward is initiated, as shown in Figure 8, withdrawing finger IIIS from the switch IE4 so that it opens to deenergize solenoid I04 which releases fluid pressure in the right end of cylinder 5|]. Preferably, for a brief subsequent interval, during which the saw is being swung forward to the point where switch III is again closed, pressure equalization occurs in the opposite ends of the cylinder. As a result, the stock-advancing platform remains stationary during this period, and its retraction is initiated an instant later when further forward movement of the saw carriage arm closes switch I IE1, energizing solenoid I02 and opening valve 93 as explained previously.

In the modified machine shown partially in Figures 9 and 10, the saw I8 and the saw carriage arm I20 derive their swinging movement from a crank or an eccentric pin I22 interconnecting a driving wheel I28 and a block I23 which is adapted to slide reciprocatively in a groove I24 formed in a driving arm I26 fixed to the carriage arm. The wheel I28 is rotated by a motor ISB which acts through a chain drive mechanism I32. The carriage swings about the drive pulley shaft I33.

As in the type of machine described previously, the stock feeding platform 44 is operated by a fluid actuated piston, and the devices are similar also in other respects. Thus, the apparatus is provided with a slider 58 coupled to the platform M by a vertical post 66 extending slidably through a hole in the slider, and with friction strips 68 pressed against the slider by the force of springs III, the slider being guided for longitudinal movement by a retaining member "I2. A form of linkage drive system for the platform different from that incorporated in the machine of Figure 1 is used in this instance. A singlelink type of toggle mechanism is employed, including links I34 spaced lengthwise of platform 44, and pivotally connected by their upper ends to the platform and by their lower ends to rod A modified arrangement of stops is also provided, for limiting the expansion and contraction of the linkage means.

The forward movement of the rod I36 is limited by an adjustable stop comprising a lug I38 extending upwardly from the slider through which lug is threaded a bolt Mi), the end of the bolt adjacent to rod I36 being positioned during its stock feeding in the path of such rod, to be engaged by such rod end. On its return stroke, the rod I36, having a downwardly projecting bolt I42 threaded into it, is stopped at the point of contact of such bolt with the end wall of a longitudinal slot I44 formed in the slider. The head of the bolt is shown as Sliding in a wider opening I46 in the slide supporting and guiding member I2, and acts to prevent the rod I36 from rising during its reciprocation.

The actuating and control means for the stock feed mechanism shown in Figure 11 includes a fluid actuating system comprising the cylinder 50 and the pipes 95 and 55 which are connected to a selector slide valve I68 controlling communication pipe I50 between a supply of fluid under pressure and the opposite ends of cylinder 50. The valve operating mechanism includes a link I52 connected between the valve and a crank pin I54 which is mounted on a disc I56 secured to the end of drive shaft I29 remote from the saw carriage arm crank wheel I28. 1y, crank I54 is rotated synchronously with, but phased at an appropriate angle from, the crank pin I22 on disc I28. The valve construction here shown represents the type in which reciprocation of the valve slider alternately connects one of pipes 94 and 96 to the supply pipe I50 and connects the other of these pipes to exhaust.

In the operation of the machine, desired delayed action of the valve I43 at its alternate sup ply positions is obtained as a result of the nature of the movement imparted to the link J52 by the crank pin I54. A similar type of movement is imparted to the saw carriage arm by the crank pin I22 in giving the saw a quick-return motion, and the arrangement provides the desired coordination between the movement of the saw and the stock feed movement effected by the action of valve I48.

Among its many advantages, both forms of the apparatus may be seen to operate in an accurate, positive and nicely regulated manner in feeding the stock. It will be understood that the novel apparatus provided by the invention in accomplishing this may be adapted in various ways to similar machines intended for other purposes.

I claim as my invention:

1. Intermittent work feed mechanism comprising an elongated generally horizontal Work support having an opening therein, a work-engageable element normally disposed beneath said support opening but guided for movement first upwardly to project through said opening into contact with, and raise, the work on said sup port, generally horizontally lengthwise of said support, to feed the work so engaged, downwardly to retract beneath said support, and then generally longitudinally to its initial position, and means intermittently operable so to move said work-engageable element to feed the work,

comprising a drive member disposed beneath Consequentsaid support and guided for reciprocation gen erally longitudinally thereof, slide means guided for reciprocation longitudinally of said support and interconnected with said work-engageable element for conjoint movement therewith longitudinally and for vertical movement of said element relative to said slide means, adjustableforce restraining means cooperating with said slide means to exert an adjustable force thereon tending to restrain longitudinal movement thereof in either direction, a link pivotally interconnecting said drive member and said workengageable element, said link being inclined at a variable angle upwardly and forwardly in the direction of work feed, from its connections on said drive member and Work-engageable element, respectively, and stop means cooperating between said reciprocable drive member and said slide means to limit positively relative longitudinal movement thereof in both directions, at opposite relative positions thereof corresponding to different angles of inclination of said link, and thereby corresponding to the extreme upper and lower positions of said work-engageable element actuated by said drive member through said links, slide means and stop means.

2. Intermittent work feed mechanism comprising an elongated generally horizontal work support having an opening therein, a workengageable element normally disposed beneath said support opening but guided for movement first upwardly to project through said opening into contact with, and raise, the work on said support, generally horizontally lengthwise of said support, to feed the work so engaged, downwardly to retract beneath said support, and then generally longitudinally to its initial position, and means intermittently operable so to move said work-engageable element to feed the work, comprising a drive member disposed beneath said support and guided for reciprocation generally longitudinally thereof, slide means guided for reciprocation longitudinally of. said support and interconnected with said work-engageable element for conjoint movement therewith longitudinally and for vertical movement of said element relative to said slide means, restraining means cooperating with said slide means to exert a force thereon tending to restrain longitudinal movement thereof in either direction, link means pivotally interconnecting said drive member and said work-engageable element, including a link inclined at a variable angle upwardly and forwardly in the direction of work feed, relative movement between said reciprocable drive mem her and said slide means in one direction eliecting swinging of said link to raise said workengageable element into contact with the work and relative movement therebctween in the opposite direction efiecting swinging of said link to lower said work-engageable element out of contact with the work.

3. Intermittent work feed mechanism comprising an elongated generally horizontal work support having an opening therein, a workengageable element normally disposed beneath said support opening but guided for movement first upwardly to project through said opening into contactwith, and raise, work on said support, generally horizontally and lengthwise of said support to feed the work so engaged, downwardly to retract beneath said support, and then generally longitudinally to its initial position, and means intermittently operable so to move said work-engageable element to feed the work.

comprising a drive member disposed beneath said support and guided for reciprocation generally longitudinally thereof, slide means guided for reciprocation longitudinally of said support and interconnected with said Work-engageable element for conjoint movement therewith longitudinally and for vertical movement of said element relative to said slide means, adjustable frictional restraining means cooperating with said slide means to exert an adjustable frictional force thereon tending to restrain longitudinal movement thereof in either direction, a toggle linkage comprising a pair of generally oppositely extending links pivotally interconnected at their adjoining ends with said drive member, and connected at their opposite ends, one to said slide means and one to said work-engageable element, said links defining a variable angle, less than 180 degrees, opening forwardly in the direction of work feed, and stop means cooperating between said reciprocable drive member and said slide means to limit positively relative longitudinal movement thereof in both directions at opposite relative positions thereof corresponding to different angles formed by said links, and thereby corresponding to the extreme upper and lower positions of said work-engageable element actuated by said drive member through said links, slide means and stop means.

4. In a machine for performing successive operations at spaced points along a length of stock, in combination with stock supporting means, a liftable platform positioned in relation to said supporting means for lifting the stock therefrom and advancing it for depositing the stock in incrementally advanced position on said supporting means, and platform actuating mechanism comprising a drive member movable parallel to the direction of advance of the stock, linkage means including a link interconnecting said platform and said drive member to raise and lower said platform into and out of contact with the work, respectively, by swinging of said link in a generally vertical plane, between different angular positions by reciprocation of said drive member, a follower member guided for reciprocation generally parallel to said drive member, means interconnecting said platform and said follower member for conjoint longitudinal reciprocation thereof in a direction parallel to the line of advance of the stock, but for relative vertical separation of said platform and follower member, means restraining movement of said follower member during swinging of said link into platform-raised position by movement of said drive member by a predetermined amount in one direction, to raise the stock from said supporting means, means thereafter operable to connect said platform and follower member with said drive member for movement conjointly in stock advancing direction by further movement of said drive member beyond said predetermined amount in the samedirection, movement of said drive member in the opposite direction effecting reverse swinging of said link and lowering of said platform to deposit the stock on said supporting means, and thereafter to return said platform and follower member to the initial position.

5. The combination defined in claim 4, wherein the follower member comprises a slider, and the restraining means comprises frictional means operatively engaging such slider to restrain longitudinal movement thereof against any force below a predetermined value, corresponding to that effective to restrain movement of said slider until 10 raising of the platform fully into stock-lifted position.

6. The combination defined in claim 5, wherein the linkage comprises a toggle linkage including a pair of oppositely extending links connected at their adjoining ends to the drive means and at their opposite ends to the platform and slider, respectively.

'7. The combination defined in claim 5, wherein the frictional restraining means comprises a friction element engageable with the slider, and spring means operable to press the friction element against said slider resiliently by a predetermined force.

8. The combination defined in claim '7, and means operable to pre-load the spring means by adjustable amounts to vary the force applied by the friction element to the slider.

9. Step-by-step work feed mechanism comprising in combination with work-supporting means and yieldable work holddown means, a work-engageable member guided for reciprocation both vertically and longitudinally to raise the work from said supporting means, advance it, redeposit it and return, a slide member guided for reciprocation only longitudinally, parallel to Work feeding movement of said Work-engageable member, a vertical guide member depending from said work-engageable member and connected to said slide member to constrain said members for conjoint longitudinal movement while permitting relative vertical movement thereof, frictional means engageable with said slide member to exert a selected restraining force against reciprocation thereof, drive means reciprocable in a direction parallel to said work-engageable and slide members, linkage means including a link pivotally interconnecting said work-engageable member and drive member and swingable between one acute angle of inclination relative to the line of reciprocation of said drive means, corresponding to lowered position of said workengageable member, and a greater acute angle of inclination thereof, corresponding to raised position of said work-engageable member, by reciprocation, forward and back, of said drive means in the direction of work feed and oppositely, respectively, and stop means operable to limit relative movement of the drive means and said slide member accompanying swinging of said link, at extreme relative positions corresponding to said angular positions of such link, respectively, restraining force on said slide member preventing longitudinal movement thereof and of said work-engageable member during swinging of said link between its said positions.

10. Mechanism defined in claim 9 wherein the holddown means comprises a weight-actuated member having a plurality of work engageable rollers, and means to lift said weight-actuated member to raise said rollers from the work simultaneously for insertion and removal of work from the supporting means.

JOE B. McFALL.

REFERENCES CITED UNITED STATES PATENTS Name Date McDowell Aug. 12, 1840 Number (Other references on following page) Number 11 UNITED STATES PATENTS Name Date Kautz Apr. 17, 1877 Kautz Feb. 5, 1884 Abbott Sept. 10, 1889 Schilbach Oct. 10, 1905 Miller Feb. 27, 1906 Bell May 2, 1911 Russ May 2, 1911 Johnson Sept. 10, 1918 Johnson Sept. 5, 1922 Number Name Date Dennis 1 May 19, 1931 Shmyrofi et 211. Sept. 27, 1932 Horstkotte July 11, 194

FOREIGN PATENTS Country Date Austria, Jan. 10, 1935 Germany Oct. 30, 1920 Germany Aug. 1, 1930 

